Sparky: I am also curious of the reason the fixtures are limited to 90º wire. I know that the older NM cable had TW 60º wires. I have never read the history, or reason for 60º wire not being acceptable. Many homeowners can not tell the difference. This appears to me, to be an irresponsible development. I hope someone can give the technical reasons for this application.
well.... apparently it's all about captive heat affecting conductors of the feeding outlet box. The articles focus is on incandesant lighting. The article mentions 410-11.
The obvious being that a hanging, or open shade fixture will dissapate the elements heat better than a closed shade cieling mounted fixture.
It is somewhat an irresponsible develpoment Ben, being that changing out a fixture is a DIY'ers usual gig. The instructions hit the round file with little consideration.
It also makes it hard on the serious field electrician, trying to explain to customers that their house wiring is NFG for any walmart fixture mama likes. I am viewed as a "carpetbagger" in those deals....
The only "code" fix is to change the wiring to 90 NM, other threads suggest the "floater" box in the cieling. This is really two wrongs trying to add to a right.
There is no gauge or exception allowing added insulation, or displacement of conductors to a defined distance as in a larger JB with pigtails,or AFCI's, or lesser elements ( would'nt last anyway).
My reading of this is that the problem arises because of the increased insulation being added to older houses. I don't think that fixture design has changed really, meaning that the existing fixtures are also a problem. I was not able to find any other mention of this problem except for that IAEI article. It seems like these warnings have crept up on all light fixtures recently and no one talks about it?
Sparky: We are in full agreement, I hope this opinion is not restricted to only us. I would prefer to have a light fixture constructed in such a manner, that heat would be prevented from commuting to the outlet box and wiring. I am sure I can do this, and others are much more intelligent than I. As you have stated, this appears like a liability disclaimer to prevent litigation. In my service work days, I had a lot of creamated wire problems in fixture outlets. This increased after the banning of asbestos. Many were injured and had there lives shortened by asbestos exposure. This is a documented fact. How many fatalities and injuries are a result of fires in these overheated outlet boxes, that asbestos insulation would have prevented? This, we will never know.
This again appears to be the old backward approach to hazard prevention, and my old pet gripe. Dealing with the effects of a problem and not focusing on the cause. I have some old pieces of asbestos sheets. These belonged to my father. He was a plumber, and often repaired copper water lines. He used these sheets to prevent ignition of the wood framing members, when soldering the connections. I used these recently, and noticed that on one side the temperature was very high. The other side would not melt butter. Unfortunately there has not been a material created that compares to this degree of heat insulation, but I know an acceptable material using proper clearance can be used to make all fixtures safe, even to compensate for higher wattage lamps being installed. I recently watched a hanging chandelier break into flames when first turned on, the first thing ignited was the UL label, the second was the "Made in China" decal.
2 wrongs don't make a right , i stand corrected here Ben. I would have mentioned asbestos, except it gives everybody a bad case of rectal lightning these days.
Not long ago, i has a job where the customer supplied the cheapest lighting he could get, all show, no go. One such item was an IC/NON-IC recessed can, the instructions stating that if i simply scrapped off the(IC/NON-IC) sticker, it would become IC rated. I had complained to the GC, and he said as long as the UL sticker was visible after the fire I need not worry.
[This message has been edited by sparky (edited 03-25-2001).]
Glad to see my original question was not so naive after all. There seems to be some real debate about how to best insure against heat damage with these high-temp fixtures. It is absolutely true (as Sparky said) that most homeowners would not give a second thought to putting in recessed lighting. I think there's an unfortunate sentiment that goes something like "if it wasn't safe for me to do they would sell it at Home Depot".
I don't know if this is a recent innovation or not, but most halogen fixtures do have a temperature cutoff whereby they begin to flicker and ultimately cut out when some critical temperature is reached (what that is I don't know). Perhaps this is the manufacturers response to the changes in insulation methods? In any case, it seems that the issue is not so black and white.